--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchingUploader.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/repositories/uploaders/BatchingUploader.java
@@ -216,16 +216,23 @@ public class BatchingUploader {
         if (isBatchFull) {
             flush(true, false);
         } else if (isPayloadFull) {
             flush(false, false);
         }
     }
 
     public void noMoreRecordsToUpload() {
+        // It's possible that we've hit a failure during an upload.
+        // If that's the case, bail out. Our delegate chain has already been notified.
+        if (shouldIgnoreFurtherRecords()) {
+            Logger.debug(LOG_TAG, "Ignoring 'no more records to upload' signal due to previous failure.");
+            return;
+        }
+
         Logger.debug(LOG_TAG, "Received 'no more records to upload' signal.");
 
         // If we have any pending records in the Payload, flush them!
         if (!payload.isEmpty()) {
             flush(true, true);
             return;
         }
 
@@ -264,27 +271,22 @@ public class BatchingUploader {
         //     - Then mark record's store as 'failed' and continue uploading
         // 2. shouldFailBatchOnFailure is false, and it failed sanity checks because it's too large,
         //     - Continue uploading, and don't fail synchronization because of this one.
         // 3. shouldFailBatchOnFailure is true, and it failed for any reason
         //     - Stop uploading.
         if (shouldFailBatchOnFailure) {
             // case 3
             Logger.debug(LOG_TAG, "Batch failed with exception: " + e.toString());
-            executor.execute(new PayloadDispatcher.NonPayloadContextRunnable() {
-                @Override
-                public void run() {
-                    sessionStoreDelegate.onRecordStoreFailed(e, record.guid);
-                    payloadDispatcher.doStoreFailed(e);
-                }
-            });
             // Send off to our delegate that we failed.
+            sessionStoreDelegate.onRecordStoreFailed(e, record.guid);
+            payloadDispatcher.doStoreFailed(e);
         } else if (!sizeOverflow) {
             // case 1
-            sessionStoreDelegate.deferredStoreDelegate(executor).onRecordStoreFailed(e, record.guid);
+            sessionStoreDelegate.onRecordStoreFailed(e, record.guid);
         }
         // case 2 is an implicit empty else {} here.
     }
 
     // Will be called from a thread dispatched by PayloadDispatcher.
     // NB: Access to `uploaderMeta.isUnlimited` is guarded by the payloadLock.
     /* package-local */ void setUnlimitedMode(boolean isUnlimited) {
         // If we know for sure that we're not in a batching mode,

--- a/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
+++ b/mobile/android/services/src/main/java/org/mozilla/gecko/sync/synchronizer/RecordsChannel.java
@@ -226,16 +226,23 @@ public class RecordsChannel implements
     } catch (NoStoreDelegateException e) {
       // Must not happen, bail out.
       throw new IllegalStateException(e);
     }
 
     // Allow this buffer to be reclaimed.
     toProcess = null;
 
+    // It's possible that one of the delegate-driven `store` calls above failed.
+    // In that case, 'onStoreFailed' would have been already called, and we have nothing left to do.
+    if (storeFailed.get()) {
+      Logger.info(LOG_TAG, "Store failed while processing records via sink.store(...); bailing out.");
+      return;
+    }
+
     // Now we wait for onStoreComplete
     Logger.trace(LOG_TAG, "onFetchCompleted. Calling storeDone.");
     sink.storeDone();
   }
 
   // Sent for "store" batches.
   @Override
   public void onBatchCommitted() {